Liquid Desiccants for Minimum Refrigerant Charge in Breweries

Abstract
Traditionally, process air-conditioning systems in breweries and other
food and beverage facilities have used distributed refrigeration systems
to maintain production areas at design set points. These systems
inherently have large refrigerant charges that cause environmental and
regulatory concerns. In addition, the maintenance costs associated with
refrigeration replenishment and leak control are relatively high.
Applications in food and beverage facilities often require refrigerant to
be delivered at or below freezing, which results in additional equipment
and maintenance costs related to coil defrost cycles and increased energy
usage due to additional heat load in the conditioned space. Liquid
desiccants such as glycol and halide salt can act as a secondary coolant
for these refrigeration systems, resulting in substantially less
refrigerant charge onsite and possible elimination of it from the
conditioned space altogether. With this approach, the refrigerant charge
remains in the powerhouse, and the desiccant or secondary coolant is piped
to and from the process areas. With the use of plate heat exchangers for
the evaporator and condenser, the refrigerant charge in these systems can
be readily reduced to <5 lb/t of cooling. In most cases, this can reduce
the refrigerant charge below the threshold for onerous reporting and
regulatory requirements.